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- Banned For Being A Troll
So why not everyone run 89... on the chance that half of us are correct
So why not everyone run 89... on the chance that half of us are correct
I'm averaging 27.5 nearly all city using 91 octane since new. I just cracked 2700 miles on my car and I can say it feels well broken in at this point. My fuel economy has also stabilized. I just filled up with 87 octane from QT to see what would happen. Maybe it's just me, my driving, my climate, the brand of gas, or the fact that I have a manual transmission, but I did notice a decrease in performance. Engine oil may make a minor difference, so note that I changed my oil at 2000 miles using Mobil 1 0w-20.
That said I don't think doing a back to back 87 vs 91 octane comparison is vaild. The ECU adjusts fueling and ignition timing to your car and climate. This correction process takes at least two full warmup cycles with varied RPMS's and load. If you change fuel grades, your engine tuning will be "off". After burning about 1/4 tank of 87, the engine seems to have adjusted itself to the different gas and performance has come back some, but not all the way. I'll go run 1 or 2 more full tanks of 87 from Chevron to see if performance returns. The 91 octane only costs me an extra $2-$3 per fillup. For even for a minor perfomance increase, l consider it money well spent with the way I drive. I'm actually quite pleased with my fuel economy so saving money is not really the issue for me. I use WOT to get up to speed on a regular basis, I refuse to impede traffic in the slightest degree.
<a href="http://www.fuelly.com/driver/leedos/cx5" target="_blank"><img src="http://mefi.us/images/fuelly/sig-us/130474.png" width="500" height="63" alt="Fuelly" title="Share and compare MPG at Fuelly" border="0"/></a>
I ran 3 tanks of 87 (Costco, QT, and Chevron) to verify that I am indeed getting worse gas mileage using 87 vs. 91. I can truthfully say that running 87 octane I'm getting around 23.8 MPG City, the dash reads slightly higher at 25.6. The dash reading being higher than actual seems to be consistent with what others are seeing as well. I accelerate more aggresviely than the EPA does so getting less that the window sticker doesn't surprise me at all. It was the same way with my last car (2002 Audi A4 1.8t).
Looking at my last three tanks of 91, I was getting 27.3 MPG 100% city. Averaging my last three tanks of 87, I'm was getting 24.5MPG with about 50 miles of highway driving. I also noticed when running 87 that my low fuel light would come on around 285 miles, running 91 it would come on around 315.
All said and done, for me, in my car, in my hot climate, driving in stop and go city traffic, filling my car with 91 octane actually cost less per mile. I get 6.901 miles per dollar running 87. I get 7.28 miles per dollar running premium. I suspect that those of you that aren't seeing any difference have the following things going for you:
1. You rarely use more the 50% throttle. Probably because you don't want your auto tranny to downshift. You just deal with or the lethargic low RPM acceleration of this car doesn't bother you.
2. Your climate is giving your lower intake air temps than I have. This helps the car run more timing. My intake air temps are around 135 degrees in the Arizona summer.
I'm not here to argue with other forum users on this, only to share my experience. It won't hurt my feelings if you think I'm full of BS and I'm playing "mind tricks" on myself. Why should you change if you are perfectly happy running 87? If you are not happy with MPG and performance and maybe you also live in a hot climate and drive a lot in stop and go why not try something different and come to your own conclusions. I'd recommend that you consider running 91 octance to improve your mileage. From my experience I've found that low RPM (less the 2500) acceleration is better and MPG is better. This will be my final post in this thread.
I ran 3 tanks of 87 (Costco, QT, and Chevron) to verify that I am indeed getting worse gas mileage using 87 vs. 91. I can truthfully say that running 87 octane I'm getting around 23.8 MPG City, the dash reads slightly higher at 25.6. The dash reading being higher than actual seems to be consistent with what others are seeing as well. I accelerate more aggresviely than the EPA does so getting less that the window sticker doesn't surprise me at all. It was the same way with my last car (2002 Audi A4 1.8t).
Looking at my last three tanks of 91, I was getting 27.3 MPG 100% city. Averaging my last three tanks of 87, I'm was getting 24.5MPG with about 50 miles of highway driving. I also noticed when running 87 that my low fuel light would come on around 285 miles, running 91 it would come on around 315.
All said and done, for me, in my car, in my hot climate, driving in stop and go city traffic, filling my car with 91 octane actually cost less per mile. I get 6.901 miles per dollar running 87. I get 7.28 miles per dollar running premium. I suspect that those of you that aren't seeing any difference have the following things going for you:
1. You rarely use more the 50% throttle. Probably because you don't want your auto tranny to downshift. You just deal with or the lethargic low RPM acceleration of this car doesn't bother you.
2. Your climate is giving your lower intake air temps than I have. This helps the car run more timing. My intake air temps are around 135 degrees in the Arizona summer.
I'm not here to argue with other forum users on this, only to share my experience. It won't hurt my feelings if you think I'm full of BS and I'm playing "mind tricks" on myself. Why should you change if you are perfectly happy running 87? If you are not happy with MPG and performance and maybe you also live in a hot climate and drive a lot in stop and go why not try something different and come to your own conclusions. I'd recommend that you consider running 91 octance to improve your mileage. From my experience I've found that low RPM (less the 2500) acceleration is better and MPG is better. This will be my final post in this thread.
I agree with V8toilet. However; I one insists on trying to prove this then I suggest the following. Run 10 full tanks of one octane gas using 10 different stations and do a statical analysis and a SD. Repeat using a different octane of your choice and do a statistical anal including a SD. Then compare to two values. Ed
People buy mid grade?
I think we MIGHT sell about 200-300 bbls of midgrade, out of the 20,000 bbls disposal we see for a day's throughput.
For this reason, it will never go into any of my vehicles. The liklihood of getting "bad" gas when buying midgrade is far higher than when buying regular or super.
Sorry man but there are too many variables like temperature, traffic, speed, wind, number of shifts, and inconsistent driving conditions in general for that test to prove anything. I can get those kind of fluctuations and not change the octane of the fuel driving the same places. When the manufacturers engineers think there will be a benefit for higher octane than they might put "use 87 octane or higher" in the owners manual. .
That only matters if your station doesn't make it's mid-grade by blending regular and premium.
So the question is this: Is midgrade blended at the pump or is it blended by the tanker truck and held in separate tank?
From what I have read, most modern stations blend on-site and do not have a separate tank.
That only matters if your station doesn't make it's mid-grade by blending regular and premium.
So the question is this: Is midgrade blended at the pump or is it blended by the tanker truck and held in separate tank?